<template>
  <div class='xtx-carousel' v-if="props.sliders && props.sliders.length">
    <ul class="carousel-body" @mouseenter="stop" @mouseleave="start">
      <li class="carousel-item" :class="{ fade: currentIndex === index }" v-for="(item, index) in props.sliders"
        :key="item.id">
        <!-- 图片轮播图 -->
        <RouterLink v-if="item.hrefUrl" :to="getCateUrl(item.hrefUrl)">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
        <!-- 商品列表轮播图 -->
        <div class="slider" v-else>
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{ goods.name }}</p>
            <p class="price">&yen;{{ goods.price }}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <a @click="toggle(1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
    <div class="carousel-indicator">
      <span @click="currentIndex = i" :class="{ active: currentIndex === i }" v-for="i in indicatorData" :key="i"></span>
    </div>
  </div>
</template>
<script setup>
import { computed, defineProps, watch, onUnmounted, ref } from 'vue'
const props = defineProps({
  sliders: {
    type: Array,
    default: () => []
  },
  duration: {
    type: Number,
    default: 3000
  },
  autoplay: {
    type: Boolean,
    default: true
  }
})
// 构建指示点的数组
const indicatorData = computed(() => {
  const arr = []
  for (let i = 0; i < props.sliders.length; i++) {
    arr.push(i)
  }
  return arr
})
// 默认显示的第1个轮播图
const currentIndex = ref(0)
// 点击左右箭头实现轮播图的切换
function toggle(step) {
  const newIndex = currentIndex.value + step
  if (newIndex < 0) {
    // 回到最后一张
    currentIndex.value = props.sliders.length - 1
    return false
  }
  if (newIndex >= props.sliders.length) {
    // 回到第一张
    currentIndex.value = 0
    return false
  }
  // 正常逻辑
  currentIndex.value = newIndex
}
// 自动播放
let timer = null // 定时器的名字
// 定时器函数
const autoPlayFn = () => {
  clearInterval(timer)
  timer = setInterval(() => {
    // 自动往右切换
    currentIndex.value++
    if (currentIndex.value >= props.sliders.length) {
      currentIndex.value = 0
    }
  }, props.duration)
}
// 鼠标离开ul时开启定时器
function start() {
  autoPlayFn()
}
// 鼠标移入ul时停止定时器
function stop() {
  clearInterval(timer)
}

watch(() => props.sliders, (newVal) => {
  // 有数据&开启自动播放，才调用自动播放函数
  if (newVal && newVal.length && props.autoPlay) {
    currentIndex.value = 0
    autoPlayFn()
  }
}, { immediate: true })

// 组件销毁时清除定时器
onUnmounted(() => {
  clearInterval(timer)
})

// 定义函数处理分类url地址
function getCateUrl(url) {
  return url.replace('category', 'cate')
}
</script>
<script>
export default {
  filters: {
    getCateUrl: function (val) {
      return val.replace('category', 'cate')
    }
  }
}
</script>
<style lang="less" scoped>
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;

  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }

    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;

      // 控制显示哪张图片
      &.fade {
        opacity: 1;
        z-index: 1;
      }

      img {
        width: 100%;
        height: 100%;
      }

      // 轮播商品
      .slider {
        display: flex;
        justify-content: space-around;
        padding: 0 40px;

        >a {
          width: 240px;
          text-align: center;

          img {
            padding: 20px;
            width: 230px !important;
            height: 230px !important;
          }

          .name {
            font-size: 16px;
            color: #666;
            padding: 0 40px;
          }

          .price {
            font-size: 16px;
            color: @priceColor;
            margin-top: 15px;
          }
        }
      }
    }

    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;

      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;

        ~span {
          margin-left: 12px;
        }

        // 控制哪个指示点高亮
        &.active {
          background: #fff;
        }
      }
    }

    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, .2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 50%;
      transform: translateY(-50%);
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;

      &.prev {
        left: 20px;
      }

      &.next {
        right: 20px;
      }
    }
  }

  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}</style>